Replace 96 doorman manifold with...

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GRWeldon

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Is an OEM manifold from a 2003 mustang 4.6 2v a plug and play without any issues? I want to replace the crappy aftermarket one that is on it...
 
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Assuming it's the original with the aluminum crossover, and it's in good condition (check for cracking in the composite parts under the crossover), you'd have to follow the original PI manifold upgrade conversion instructions.

Basically, you need the PI valley heater tube and nipple, PI manifold gaskets, and some RTV to patch the coolant passageway where the shape changed (basically use the gasket as a guide to ensure it seals). You lose a couple ft-lb of low-end torque, but the engine breathes way better above 3500-4000 and typically 10-12 HP is added.
 
You can also just use heater hose under the intake and assemble a couple nylon elbows/couplings and such to connect heater lines. It will have to route along the left side(drivers side) a little off the valley but under the runners.
 
This is the best (only?) video I've seen on the swap. It walks you through everything you need to do. I think he was on the old board. I don't know if he is over here. Just click on the link to watch in on YouTube's site.
 
heaterhose dies pretty quickly in the valley; that is why ford went to a hard line.
 
After watching the video, I think the best course of action would be to scrounge some PI heads and do the whole 9 yards. Especially since the car needs valve seals anyway. I'll put it on the list, which means it probably won't get done. Thanks everybody for the input!
 
GRWeldon said:
After watching the video, I think the best course of action would be to scrounge some PI heads and do the whole 9 yards. Especially since the car needs valve seals anyway. I'll put it on the list, which means it probably won't get done. Thanks everybody for the input!
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On a 96 you could just put PI cams in and get the same power as a PI motor paired with the intake. PI heads don’t actually flow meaningfully better than 96+ npis, all you gain from a headswap is the extra point in compression and about 10 horsepower, but you also need to run premium gas. PI heads should also be tuned as the combustion chamber changes enough where imthey don’t want as much spark advance as even the stock npi head tune has.
 
XR7-4.6 said:
On a 96 you could just put PI cams in and get the same power as a PI motor paired with the intake. PI heads don’t actually flow meaningfully better than 96+ npis, all you gain from a headswap is the extra point in compression and about 10 horsepower, but you also need to run premium gas. PI heads should also be tuned as the combustion chamber changes enough where imthey don’t want as much spark advance as even the stock npi head tune has.
Click to expand...
I agree with that. There is very little apples to apples flow data on the NPI versus PI heads. I think a lot of people just assume they flow way better because the PI engines make more power. I personally wouldn't want to have to deal with running higher grade fuel if I didn't have to. If you have the gumption to do it in the car I agree that PI cams and valve seals on the heads you have would be the way to go. The coolant port mismatch on the NPI heads and PI intake is easily handled with two appropriately located dabs of RTV. The hard part is finding a real Ford PI intake that A) somebody isn't asking ridiculous money for and/or B) is in good shape. Good deals are still out there though.
 
I've swapped two cars, and the dab of rtv works great.
 
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